Optimizing PFAS Plume Remediation: Gas Sparging and Partially Penetrating Pump‐and‐Treat Systems

Per‐ and polyfluoroalkyl substances (PFAS) represent a major challenge in groundwater remediation due to their persistence, mobility, and large number of potentially impacted sites. When PFAS plume remediation is required, pump‐and‐treat (P&T) systems using granular activated carbon (GAC) or other ex situ separation or destruction technologies are common options. However, these systems may require operation for decades and the pumping of large volumes of water. This paper presents an approach to more efficiently capture and treat PFAS plumes by using gas sparging to concentrate PFAS in the upper portion of the aquifer, followed by a shallow extraction approach using partially penetrating wells designed to pump only the upper, concentrated zone. A web‐based Capture Zone Calculator Tool was developed based on published graphical capture zone curves in the groundwater literature to determine minimum pumping rates for both fully and partially penetrating wells, showing reductions in required pumping rates when PFAS are concentrated in a thinner zone. Cost estimates using the United States Environmental Protection Agency (USEPA) GAC costing model for three AFFF‐impacted sites suggest that incorporating gas sparging could reduce total project costs by up to 24% over a 20‐year period. These findings indicate that a “gas sparging + targeted pump‐and‐treat” strategy is technically feasible and may offer modest economic benefits for PFAS plume containment. However, the potential cost savings may not be sufficient to drive widespread adoption. As a result, the primary role of gas sparging in PFAS remediation may be to mobilize PFAS from groundwater into the vicinity of the water table, either as a standalone method or combined with sorbents placed near the capillary fringe.